interface BasePolygon {
    default void display() {
        System.out.println("This is a Polygon");
    }
}

interface Polygon extends BasePolygon {
    abstract double calculateArea();
}

public class Rectangle implements Polygon {

    private double width;
    private double height;

    public Rectangle(double height, double width) {
        this.height = height;
        this.width = width;
    }

    @Override
    public double calculateArea() {
        return width * height;
    }

}